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[35.247.111.240]) by smtp.gmail.com with ESMTPSA id s3sm2254541pfu.9.2021.05.20.08.04.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 May 2021 08:04:15 -0700 (PDT) Date: Thu, 20 May 2021 15:04:11 +0000 From: Sean Christopherson To: Krish Sadhukhan Cc: kvm@vger.kernel.org, pbonzini@redhat.com, jmattson@google.com Subject: Re: [PATCH 4/4 v2] KVM: x86: Add a new VM statistic to show number of VCPUs created in a given VM Message-ID: References: <20210520005012.68377-1-krish.sadhukhan@oracle.com> <20210520005012.68377-5-krish.sadhukhan@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210520005012.68377-5-krish.sadhukhan@oracle.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, May 19, 2021, Krish Sadhukhan wrote: > 'struct kvm' already has a member for counting the number of VCPUs created > for a given VM. Add this as a new VM statistic to KVM debugfs. Huh!?? Why? Userspace is the one creating the vCPUs, it darn well should know how many it's created. > Signed-off-by: Krish Sadhukhan > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/svm/svm.c | 3 +-- > arch/x86/kvm/x86.c | 1 + > virt/kvm/kvm_main.c | 2 ++ > 4 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index a19fe2cfaa93..69ca1d6f6557 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1139,6 +1139,7 @@ struct kvm_vm_stat { > ulong nx_lpage_splits; > ulong max_mmu_page_hash_collisions; > ulong vcpus_ran_nested; > + u64 created_vcpus; > }; > > struct kvm_vcpu_stat { > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index d1871c51411f..fef0baba043b 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -3875,8 +3875,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) > > /* Track VMRUNs that have made past consistency checking */ > if (svm->nested.nested_run_pending && > - svm->vmcb->control.exit_code != SVM_EXIT_ERR && > - svm->vmcb->control.exit_code != SVM_EXIT_NPF) { > + svm->vmcb->control.exit_code != SVM_EXIT_ERR) { ??? > if (!vcpu->stat.nested_runs) > ++vcpu->kvm->stat.vcpus_ran_nested; > ++vcpu->stat.nested_runs; > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index cbca3609a152..a9d27ce4cc93 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -258,6 +258,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { > VM_STAT("nx_largepages_splitted", nx_lpage_splits, .mode = 0444), > VM_STAT("max_mmu_page_hash_collisions", max_mmu_page_hash_collisions), > VM_STAT("vcpus_ran_nested", vcpus_ran_nested), > + VM_STAT("created_vcpus", created_vcpus), > { NULL } > }; > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 6b4feb92dc79..ac8f02d8a051 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -3318,6 +3318,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) > } > > kvm->created_vcpus++; > + kvm->stat.created_vcpus++; > mutex_unlock(&kvm->lock); > > r = kvm_arch_vcpu_precreate(kvm, id); > @@ -3394,6 +3395,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) > vcpu_decrement: > mutex_lock(&kvm->lock); > kvm->created_vcpus--; > + kvm->stat.created_vcpus--; > mutex_unlock(&kvm->lock); > return r; > } > -- > 2.27.0 >